In September, Microsoft announced the launch of Windows 10 subscriptions for its business customers, with prices starting at $7 per user per month. The company made those subscriptions available through its Cloud Solution Provider (CSP) network, encouraging "businesses of any size" to take advantage of its new offering, promising a range of advantages.

Today, Microsoft has revealed that subscribers through its CSP program can now enjoy a new benefit: the ability to "upgrade their Windows 7 and Windows 8.1 PCs and devices to Windows 10 at no additional cost."

This offer is available to customers with Windows 10 Enterprise E3 and E5 subscriptions, as well as Secure Productive Enterprise E3 and E5.

Previously, Microsoft required these customers to purchase a new Windows 10 license for older machines that they wished to upgrade from Windows 7 or 8.1. Now, Microsoft is effectively offering them a 'free' upgrade path to the new OS, so that they can then be managed and maintained under its Windows 10 subscription programs.

Microsoft also emphasized that "the Windows 10 upgrade licenses issued as part of this process are perpetual", adding that they "will not expire or be revoked" if the customer later decides to terminate their Windows subscription.

That will greatly reduce the expense of upgrading to Windows 10 for many organizations that are still relying heavily on older PCs and other hardware that doesn't yet need to be replaced. Until now, they faced the choice of either purchasing a new Windows 10 license for those older machines, replacing them with new Windows 10 PCs, or continuing to use their existing devices with the older operating systems.